/* * Watchdog driver for Atmel AT32AP700X devices * * Copyright (C) 2005-2006 Atmel Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #define TIMEOUT_MIN 1 #define TIMEOUT_DEFAULT CONFIG_AT32AP700X_WDT_TIMEOUT #define TIMEOUT_MAX 2 /* Watchdog registers and write/read macro */ #define WDT_CTRL 0x00 #define WDT_CTRL_EN 0 #define WDT_CTRL_PSEL 8 #define WDT_CTRL_KEY 24 #define WDT_CLR 0x04 #define WDT_BIT(name) (1 << WDT_##name) #define WDT_BF(name,value) ((value) << WDT_##name) #define wdt_readl(dev,reg) \ __raw_readl((dev)->regs + WDT_##reg) #define wdt_writel(dev,reg,value) \ __raw_writel((value), (dev)->regs + WDT_##reg) struct wdt_at32ap700x { void __iomem *regs; int timeout; int users; struct miscdevice miscdev; }; static struct wdt_at32ap700x *wdt; /* * Disable the watchdog. */ static void inline at32_wdt_stop(void) { unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); } /* * Enable and reset the watchdog. */ static void inline at32_wdt_start(void) { /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | WDT_BF(CTRL_PSEL, psel) | WDT_BF(CTRL_KEY, 0x55)); wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | WDT_BF(CTRL_PSEL, psel) | WDT_BF(CTRL_KEY, 0xaa)); } /* * Pat the watchdog timer. */ static void inline at32_wdt_pat(void) { wdt_writel(wdt, CLR, 0x42); } /* * Watchdog device is opened, and watchdog starts running. */ static int at32_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(1, &wdt->users)) return -EBUSY; at32_wdt_start(); return nonseekable_open(inode, file); } /* * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then * the watchdog is also disabled. */ static int at32_wdt_close(struct inode *inode, struct file *file) { #ifndef CONFIG_WATCHDOG_NOWAYOUT at32_wdt_stop(); #endif clear_bit(1, &wdt->users); return 0; } /* * Change the watchdog time interval. */ static int at32_wdt_settimeout(int time) { /* * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is * 2 ^ 16 allowing up to 2 seconds timeout. */ if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) return -EINVAL; /* * Set new watchdog time. It will be used when at32_wdt_start() is * called. */ wdt->timeout = time; return 0; } static struct watchdog_info at32_wdt_info = { .identity = "at32ap700x watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, }; /* * Handle commands from user-space. */ static int at32_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; int time; void __user *argp = (void __user *)arg; int __user *p = argp; switch (cmd) { case WDIOC_KEEPALIVE: at32_wdt_pat(); ret = 0; break; case WDIOC_GETSUPPORT: ret = copy_to_user(argp, &at32_wdt_info, sizeof(at32_wdt_info)) ? -EFAULT : 0; break; case WDIOC_SETTIMEOUT: ret = get_user(time, p); if (ret) break; ret = at32_wdt_settimeout(time); if (ret) break; /* Enable new time value */ at32_wdt_start(); /* fall through */ case WDIOC_GETTIMEOUT: ret = put_user(wdt->timeout, p); break; case WDIOC_GETSTATUS: /* fall through */ case WDIOC_GETBOOTSTATUS: ret = put_user(0, p); break; case WDIOC_SETOPTIONS: ret = get_user(time, p); if (ret) break; if (time & WDIOS_DISABLECARD) at32_wdt_stop(); if (time & WDIOS_ENABLECARD) at32_wdt_start(); ret = 0; break; } return ret; } static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { at32_wdt_pat(); return len; } static const struct file_operations at32_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .ioctl = at32_wdt_ioctl, .open = at32_wdt_open, .release = at32_wdt_close, .write = at32_wdt_write, }; static int __init at32_wdt_probe(struct platform_device *pdev) { struct resource *regs; int ret; if (wdt) { dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n"); return -EBUSY; } regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) { dev_dbg(&pdev->dev, "missing mmio resource\n"); return -ENXIO; } wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL); if (!wdt) { dev_dbg(&pdev->dev, "no memory for wdt structure\n"); return -ENOMEM; } wdt->regs = ioremap(regs->start, regs->end - regs->start + 1); wdt->users = 0; wdt->miscdev.minor = WATCHDOG_MINOR; wdt->miscdev.name = "watchdog"; wdt->miscdev.fops = &at32_wdt_fops; if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) { at32_wdt_settimeout(TIMEOUT_MAX); dev_dbg(&pdev->dev, "default timeout invalid, set to %d sec.\n", TIMEOUT_MAX); } ret = misc_register(&wdt->miscdev); if (ret) { dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); goto err_register; } platform_set_drvdata(pdev, wdt); wdt->miscdev.parent = &pdev->dev; dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs); return 0; err_register: kfree(wdt); wdt = NULL; return ret; } static int __exit at32_wdt_remove(struct platform_device *pdev) { if (wdt && platform_get_drvdata(pdev) == wdt) { misc_deregister(&wdt->miscdev); iounmap(wdt->regs); kfree(wdt); wdt = NULL; platform_set_drvdata(pdev, NULL); } return 0; } static void at32_wdt_shutdown(struct platform_device *pdev) { at32_wdt_stop(); } #ifdef CONFIG_PM static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) { at32_wdt_stop(); return 0; } static int at32_wdt_resume(struct platform_device *pdev) { if (wdt->users) at32_wdt_start(); return 0; } #else #define at32_wdt_suspend NULL #define at32_wdt_resume NULL #endif static struct platform_driver at32_wdt_driver = { .remove = __exit_p(at32_wdt_remove), .suspend = at32_wdt_suspend, .resume = at32_wdt_resume, .driver = { .name = "at32_wdt", .owner = THIS_MODULE, }, .shutdown = at32_wdt_shutdown, }; static int __init at32_wdt_init(void) { return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe); } module_init(at32_wdt_init); static void __exit at32_wdt_exit(void) { platform_driver_unregister(&at32_wdt_driver); } module_exit(at32_wdt_exit); MODULE_AUTHOR("Hans-Christian Egtvedt "); MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);